Fix the pumps

Wednesday, July 20, 2011

No surprise, Part 2

Over the last two years, we've learned many, many of the Corps' 54 hydraulic pumps have been leaking oil into Lake Pontchartrain as they rust away. Sometimes the Corps reports these spills - as they must under federal law - and sometimes they don't. And sometimes pumps are scheduled to come out for rebuilding, while other times pumps are yanked as a result of spilling oil.

The places oil can leak out on these pumps are numerous. They include a slew of different pipes on each pump through which hydraulic oil (which powers the pumps) flows; most of that piping sits in the brackish water of the lake 24 hours a day. When the pumps aren't running, the oil sits in the piping on the pumps and in the hundreds of feet of pipes leading away and from the pumps, all the way back to the reservoirs on the hydraulic power units (HPU's) located on the land sides of the canals.

The ongoing corrosion of these completely or partially immersed pump-mounted pipes, which were carbon steel when originally installed, leads directly to leaks. While the Corps has had their contractor yank out 25 of the 40 major 60" pumps located across all three sites (three of them twice) and replaced that carbon steel piping with stainless steel, the remaining 15 60" pumps still have the rust-friendly carbon steel piping on them. As we've seen in earlier posts, the salt water does a number on this piping:

That photo is of an oil cooler on pump W5 or W6 from the 17th Street site. It was taken a mere two and half years after these pumps were accepted for service by the Corps. In actuality, the pumps started spending time in the lake waters in mid-2006, but they were taken out and put back in so many times over the following year while dealing with deep-seated design issues (some of which remain unresolved to this day) that the corrosion clock only started started running consistently in the latter half of 2007.

There are many, many more pictures of rusty pipes like this from the Conhagen repair reports:

With all this rust causing all these oil leaks, it makes sense to ask, "If the oil is leaking out of the pumps, doesn't that mean water is leaking into them?"

The answer is "Yes." When the pumps are not running, the oil is not pressurized by the HPU's. So oil can seep out of leak points and water can come in. If the Corps turns on the pumps with those leaks and starts circulating all this oil mixed with water through the entire hydraulic oil loop, the water gets into the delicate parts on the HPU and can do serious damage.

That's why it should be a standard part of the repair to completely flush out the entire hydraulic loop for any pump that get's pulled out for repairs. That would include all the connecting piping from the pump back to the onshore HPU, as well as the HPU itself. Natually, though, the Corps doesn't do this. It's too expensive (for them, not for normal engineering organizations). When the pumps were put in back in 2006, there was pickling fluid remaining in the pipes when they were intially filled with oil. The resulting jello-like muck took two flushings to remove, at an expense of hundreds of thousands of dollars paid for by the U.S. taxpayer, despite the problem totally coming out the vendor's poor performance. I imagine that expense is what keeps the Corps from cleaning out the connecting pipes every time they yank out a pump for rebuilding.

So that just adds one more question about the performance of these things if they're ever needed in a major storm (earlier storms when they were turned on were absolute pea shooters). And it should come as no surprise that problems have cropped up directly related to contaminated oil.

On December 9, 2010, the Corps issued task order #7 on the second Healtheon/Conhagen pump repair contract (there have been three such contracts - more evidence of the Corps inability to plan ahead). The task order called for the rebuilding of London Avenue pumps E2 and E6.

I detailed the facts surrounding this set of repairs in my earlier post, "The latest on lakefront pump repairs." While there were some bumps along the way during these repairs, including apparently two oil spills totalling 125 gallons, the repairs themselves seemed to go somewhat smoothly (except for a distinct lack of information on the Rineer hydraulic motors). As expected, the pumps were in terrible condition when pulled out. In fact, one of the sample pictures above of really bad rust was taken from the Conhagen repair report for these two pumps:

The pumps were put back in the canal January 24, 2011.

However, that wasn't the end of the story. Just about a week after the pumps returned to service, the Corps issued $22,188.68 modification 2 to task order #7, increasing the cost for the repair of these two pumps to $304,898.07. The scope for the modification, knowing what we know about the oil leaks on all these pumps, should come as no surprise:
"- Take oil sample out of reservoir have analysis performed.
- Drain and pump oil out of reservoir, hoses, piping, etc. and flush to remove all contaminated oil.
- Remove the hydraulic pump, motor, coolers, and piping and flush to remove all contaminated oil.
- Dispose of contaminated oil
- Furnish new replacement hydraulic oil
- Refill reservoir on test unit
- Provide standby crane for this additional work.

Completion Date:
Work shall be completed within one week from the modification effective date."

The verbiage of the task order, as well as its price, lend itself to a couple of interpretations:

1) The Corps discovered the oil in either the E2 or E6 hydraulic loops at the London Avenue site was contaminated and had Conhagen remedy the situation. The fact that this modification was issued a week after the pumps were acceptance tested argues for this, although admittedly the Corps has a long history of post-dating their contract actions.

2) Conhagen, while they were pressure testing the pumps at their facility in Kenner, LA with one of the Corps' spare hydraulic power units, encountered a problem with contaminated oil and remedied it. The mention of the reservoir on the "test unit" argues for this. We have a picture of what a typical oil pressure test at Conhagen's site looks like, from the repair report for 17th Street pumps W4 and W7:

Whether the contaminated oil was encountered at Conhagen's shop, or out at the site, the larger point about likely widespread oil contamination still stands. and adds just one more question mark above the potential future performance of these pumps.



Post a Comment

<< Home

Go to older posts Go to newer posts